Temporary physical connections of two devices to each other are common in a number of fields of technology. One area is the charging of batteries in vessels, such as vehicles like automobiles. Other areas where this may be of interest can be for providing electric power to a piece of electrically operated equipment. Another example is the filling of a tank with a liquid, such as gas or burning oil. In these and other cases there may exist an interest in conveying additional data in both directions between the devices. This may for instance be of interest when a quantity of a physical entity is transported from one of the devices to the other, where the entity can be electrical energy or a liquid such as oil and gas. There are many reasons why such data may need to be transmitted. One reason may be for economy, in order to perform an economical transaction associated with the transport. Another reason may be in order to control the quantity being transferred.
Such data can be transferred using extra wired communication and in the case of electrical charging also power line communication. Extra wires are complicated, expensive and lead to the use of additional connectors or to mixing of communication wires with power lines in one cable. Power line communication involves additional hardware for modulating the data on the electrical voltage. Both these measures involve additional work and also increased risks. Power line communication is furthermore only possible to use if electricity is involved.
The best choice is in many situations therefore to provide such additional data using a wireless connection.
Cyriacus Bleijs describes the use of power line communication in relation to charging of vehicles in “Low-cost charging systems with full communication capability”, EVS24, Stavanger, Norway, May 13-16, 2009. The document also describes wireless communication, however not between temporarily connected devices such as vehicle and a charging post.
When providing a wireless connection, it is important that it is set up between the two devices in question and no other devices.
There is therefore a need for providing a unique identification in relation to the two devices being connected to each other for enabling a wireless connection to be set up between them.
There exist techniques for identifying devices.
For instance, in relation to wireless connections and electrical charging of a vehicle, there exist technologies for identifying the vehicle.
As is described in CN 201210314 a vehicle may be provided with a Radio Frequency IDentification (RFID) tag and a cable of a charging post may be equipped with an RFID reader. As a charging cable is connected to a charging socket on the vehicle, the RFID reader detects the RFID tag of the vehicle and reads vehicle ID relevant information, like license plate information.
RFID technology can also be combined with power line communication. This is described in JP 2006245983. Here a wall socket incorporates a PLC modem for power line communication. The socket also has a reader for reading an RFID tag of an RFID plug.
US 2007/0221730 describes computer cables provided with RFID tags. A cable socket is provided with an RFID reader in order to identify the cables for ensuring that the correct cable is inserted in the right socket.
However, none of these documents are related to providing identifiers to be used for wireless communication.
In view of what has been described above, there is therefore still a need for allowing two temporarily connected devices to be able to communicate wirelessly with each other even though they are unknown to each other.